ENERGY-RELEASE RATE DETERMINATION FOR EDGE DELAMINATION UNDER COMBINED INPLANE, BENDING AND HYGROTHERMAL LOADING .1. DELAMINATION AT A SINGLE INTERFACE

Edge delamination in composite laminates subjected to combined inplane , bending and hygrothermal loading is analyzed using a crack tip eleme nt approach. Classical laminated plate theory is utilized for the crac k tip element formulation. Individual energy release rate components a re found using a set of closed form equations derived from plate theor y, plus the results from a single continuum analysis. For those cases where a linear elastic solution predicts a near-field oscillatory sing ularity, a new approach is used which allows a unique, physically mean ingful value of fracture mode ratio to be defined.